MOA In a pulmonary diffusion capacity test, the diffusing capacity for carbon monoxide (Dlco) assesses the rate at which oxygen is transferred from the lung to the pulmonary capillary bed. In a neon gas analyzer, the mixture of carbon monoxide, neon gas, oxygen, and the balance nitrogen is inhaled by the individual and is eventually exhaled after being held at near full inspiration for brief seconds. The concentrations and ratio of carbon monoxide and neon is measured in the alveolar fraction of the expired gas. The change in the concentration of the tracer gas reflects the mean alveolar carbon monoxide concentration at the start of the breath hold and provides a measure of alveolar volume by gas dilution [T183]. ; ; Neon ion radiotherapy has high linear energy transfer thus produces biological behaviour similar to neutron beams [A32763]. The rays are associated with a reduction in the oxygen enhancement ratio, which allows for more specificity for hypoxic cells, less variation in cell-cycle related radio sensitivity, and less capability for repair of radiation injury [A32763].